Among the variety of bakery products, puff pastries are quite unique. Puff pastries are laminated products with a distinctly layered structure. They are very light, and flaky. During baking, puff pastries can significantly increase in height, typically up to eight-fold. In order to form the distinct layered structure, the puff pastry dough consists of many layers of sheeted dough separated by layers of fat.
During the baking process, steam is formed from the water component in the puff pastry dough. When the water evaporates, the dough layers expand. The dough layers are insulated by the fat layers. Such a layering structure of the puff pastry dough allows each of the dough layers and fat layers to cook individually, puffing the pastry. Furthermore, as the gluten in the flour component coagulates in the preparation process, it permits the baked puff pastries to form into a light open structure with fine layers.
For centuries, Danish and French puff pastries have been made from animal fats or oils displaying certain plastic properties which would enable the fat or oil to be layered or laminated, thus creating a flaky pastry. Butter was commonly used, followed by blends of beef fats, lard, and marine oil. However, since about twenty five years ago, medical research has shown that consumption of large amounts of animal fat has major effects upon human health. Due to such medical concerns, the baking industry has pushed for the use of vegetable oil as a replacement.
Since many cooking applications, particularly baked products, require the use of solid fats, the food industry hydrogenates the vegetable oils to produce margarines, shortenings, shortening oils, and partially hydrogenated vegetable oils. Hydrogenation allows manufacturers to start with inexpensive, readily available oils and to turn these into products that compete with butter in spreadabillity and organoleptic quality. As is known to those skilled in the art, spreadability is used to describe products having plastic properties.
In hydrogenation, vegetable oils are exposed to hydrogen at a high temperature and in the presence of a catalyst. At the molecular level, when complete hydrogenation occurs, all the double bonds in the oil are saturated with hydrogen. When partial hydrogenation occurs, only some of the double bonds in the oil are converted into single bonds, while other double bonds are converted from the cis- to trans-configuration. Both of these effects straighten out the molecules so they can lie closer together and become solid rather than liquid.
Unfortunately, margarines, shortenings, shortening oils and partially hydrogenated vegetable oils which are produced from hydrogenation of oils contain large quantities of trans-fatty acids and other altered fat substances which have also been found to be detrimental to human health because they interfere with normal biochemical processes. In fact, consumption of hydrogenated fats increases a person's cholesterol level. Studies have found that large consumption of trans-fatty acids, in particular, causes an increase in cholesterol, decrease in beneficial high-density lipoprotein (HDL), interfere with the liver's detoxification system, and interfere with essential fatty acid (EFA) function. Despite these known medical concerns, the food industry still continues to use the hydrogenation process as it allows cheap oils to be turned into semi-liquid, plastic, or solid fats with specific organoleptic properties, texture, spreadability and very long shelf-life. In fact, the shelf-life of such hydrogenated and partially hydrogenated fats and oils are so extensive as compared to unhydrogenated fat and oil that those of skilled in the art have coined the term “dead” to these hydrogenated fats and oils. Due to the stability of these hydrogenated fats and oils, they are very difficult to break down in the human's digestive system. Thus, over time, these substances become detrimental to the human's health. However, hydrogenated fats and oils are favoured by the food industries as they do not spoil easily as compared to unhydrogenated fats and oils, which are much more marketable from the manufacturers' point of view.
Although butter has a small amount of trans-fatty acids which are created in the ruminant part of the cow's digestive system, research has indicated that such natural trans-fatty acids, which are not created from hydrogenation, are less detrimental to the human health.
Choosing a suitable fat system for use in puff pastries, in particular, is difficult. The baking industry recognizes that many consumers are concerned with the presence of hydrogenated or partially hydrogenated fats or oils in baked products, and puff pastries are no exception. Another difficulty in choosing a suitable fat relates to the melting point of such a fat system. It has been found that if the melting point of the fat system incorporated in the pastry dough is far beyond the human body temperature, the baked products obtained would have a waxy and unpleasant “mouth feel”.
In the recent past, the fat system incorporated in the puff pastry dough is typically 100% beef tallow, 100% of vegetable oil, or a mixture of the two. Before the fat is rolled into the dough, the roll-in type fats would have to be “chill roll” cooled such that when kneaded with the dough, a plasticity characteristic of the dough is obtained.
In U.S. Pat. No. 5,780,084 issued to DEGLI ANGELI et al. on Jul. 14, 1998, a process for preparing layered and puffed pastry products is taught. The process includes producing a dough by mixing a raw material with water in which the raw material does not contain a wheat flour, shaping the dough into a plurality of layers so as to obtain a layered dough, baking the layered dough in a thermocycle oven and drying the baked layered dough with microwaves, radio waves or infrared waves to obtain a layered and puffed pastry product.
In U.S. patent application Ser. No. 2001/0022984 A1 published by FERRARI-PHILIPPE et al. on Sep. 20, 2001, a process for the preparation of a dough for obtaining a puff pastry type product is taught. The process includes the steps of: (a) combining flour, salt, acidic proteins and an inactivated fermentation agent at room temperature; (b) adding lumps of fat to the mixture in step (a) to obtain a heterogeneous dough; (c) incorporating water into the dough; (d) extruding the dough; and (e) storing the puff pastry obtained at a temperature of −40 to +10° C.
In U.S. Pat. No. 5,080,915 issued to ZOCK on Jan. 14, 1992, a method for preparing a puff pastry in which the puff pastry is formed using flour while adding water and a fat composition is taught. The fat composition comprises fat and vegetable fibre material in a weight ratio between 1:1 and 20:1 in which the vegetable fibre material is wheat bran.
In U.S. Pat. No. 4,622,226 issued to KE et al. on Nov. 11, 1986, a process for producing a puff pastry is taught. The puff pastry is made from a multi-layered laminate which comprises alternating layers of a dough and a roll-in shortening. The flour in the dough is partially substituted with dextrin such as tapioca dextrin, potato dextrin, sago dextrin, wheat dextrin, sorgum dextrin, and corn dextrin.
It will be apparent from the foregoing prior art that the plasticity property of the puff pastry is obtained from hydrogenated and/or partially hydrogenated fat or oil.